Australia is among the highest per capita greenhouse gas-emitting countries in the world, with buildings contributing approximately 25 per cent of the nation’s total emissions.
To combat this, the National Construction Code (NCC) has implemented changes aimed at enhancing the efficiency of Australian buildings. In this regard, the built environment has cast its focus on natural ventilation and window automation, which are increasingly seen as essential strategies for improving energy performance and indoor air quality.
Window automation facilitates the efficient use of natural airflow for heating and cooling, allowing buildings to take advantage of natural cooling during warmer months.
High-quality window systems prevent uncontrolled air leakage and heat loss, reducing dependency on mechanical heating and cooling.
According to the Whole Building Design Guide, in favourable climates and building types, natural ventilation can be used as an alternative to air conditioning, saving 10 to 30 percent of total energy consumption.
Research from the US published in Energy Procedia has further found that fully automatic window systems can achieve a cooling energy saving of up to 80 per cent.
The study confirmed the superior performance of a fully automatic natural ventilation control system as opposed to manual control.
“One of the most important factors for high-performance natural ventilation is the operation of windows,” the study said.“This issue is especially prominent in mixed-mode buildings.”
As building regulations evolve and the industry delivers on the push for sustainable building practices, the adoption of automated window systems is expected to rise.
The advancements in building automation systems promise to monitor and optimise indoor environments, energy use, and cost savings.
These systems can include features such as rain and wind sensors, which automatically close windows during adverse conditions.
They can also be programmed to open when mechanical heating or cooling is switched off, allowing outdoor air to naturally regulate indoor temperatures.
According to research by Australia’s University of Wollongong and Denmark’s University of Aalborg, building automation systems can communicate with each other, return control to the user, and give feedback, enhancing user trust and system effectiveness.
The researchers said: “Automated window control opening systems, with integrated smart algorithms, have high saving potential for ventilation and cooling.”This approach not only enhances energy efficiency but also contributes to occupant comfort and health.
However, the study also pointed out that many existing models for window opening behaviour are based on moderate climates, which may not fully capture the complexities of Australian conditions.
“Most developed models refer to office buildings and moderate climates,” the study said, indicating a need for tailored solutions that consider local environmental factors.
THE HEALTH BENEFITS OF NATURAL AIR
Research has found that besides the environmental benefits, natural ventilation also contributes to healthier indoor climates which lead to improvements in occupant wellbeing.
Since Australians spend approximately 90 per cent of their time indoors, making indoor air quality (IAQ) is a crucial aspect of health and wellbeing.
Poor IAQ can lead to a range of health issues, including respiratory diseases and ‘sick building syndrome’.
Occupants in naturally ventilated residential buildings have larger comfort acceptability and suffer less from symptoms associated with this syndrome, compared to those in conditioned spaces.
The NCC mandates suitable openings for ventilation to maintain adequate air quality. Natural ventilation systems, particularly those enhanced by automated controls, can cycle out stale air and indoor pollutants, improving overall health outcomes.
Research has shown significant productivity gains associated with improved ventilation. For instance, a Harvard study found that employees working in environments with improved ventilation performed 61 per cent better on cognitive tasks than in standard office conditions.
This improvement in cognitive performance was attributed to reduced levels of carbon dioxide and other emissions from office equipment and building materials. By doubling the ventilation in the improved environment, cognitive performance was boosted by over 100 per cent.
THE EFFECTS OF WINDOW ORIENTATION ON INDOOR AIRFLOW
In the realm of architectural design, the orientation of building openings can significantly influence indoor air quality and comfort.
Factors such as wind speed, direction, and temperature vary dramatically depending on the placement of these openings.
This makes it essential to investigate the positioning of windows to determine the optimal angle for maximising natural ventilation.
The study found that windward openings are beneficial for cross-ventilation, while leeward openings provide better airflow for single-sided ventilation.
In high-rise buildings, where wind speeds are often higher, the design of windows becomes even more critical.
However, as building heights increase, safety regulations often limit the size of operable façade openings. Consequently, many turn to mechanical ventilation systems to maintain thermal comfort.
The study noted that higher levels experience higher outdoor wind velocity magnitudes, which can limit the effectiveness of natural ventilation if not properly designed.
The researchers also highlighted that still air leads to higher humidity in the deeper part of the unit, underscoring the importance of adequate window placement.